[.Euphorbia prostrata Aiton; E. chamaesyce sensu American authors, non L.]
(nat) Prostrate spurge
Mat-forming annual herbs; stems often purplish, prostrate, 0.07-0.2 m long, crisp- pubescent to pilose or sometimes glabrate. Leaves oblong to ovate-oblong, 3-9 mm long, 1.5-5 mm wide, sparsely pubescent or sometimes glabrate, margins serrate, apex rounded or obtuse, base rounded, petioles 5-1 mm long, stipules ± distinct, yellowish to purplish, linear-lanceolate, 1-2 mm long, ciliate. Cyathia solitary at nodes of short, congested, leafy, lateral shoots; involucre purple, 0.4-0.7 mm high, sparsely villous or glabrous, glands 4, maroon, suborbicular, 0.05-0.15 mm long, appendages minute, pinkish white, shorter than the gland is wide; staminate flowers 2-5 per cyathium. Capsules ovoid, 3-angled, 1-1.4 mm long, pilose on the angles, otherwise glabrous. Seeds gray to tan, narrowly ovoid, strongly 4-angled, ca. 1 mm long, the faces strongly ridged. [2n =18, 20.] Native from southern United States to South America, the West Indies, and the Paleotropics; in Hawaii naturalized and relatively common in low elevation, dry, disturbed sites on Midway Atoll and all of the main islands except Niihau and Molokai, perhaps more widespread. First collected on 0‘ahu in 1909 CForbes 1023.0, BISH).—Plate 82.
Plants of this species in Hawaii that are infected by a fungus often have erect or ascending stems.